New algorithm inspired by original code with inline comments in fields

[kapulkin]

Issue #13 fix

[t3rn0]

Wow. That's huge:)
Could you also write some tests showing what has changed? It will just be much easier to understand

[kapulkin]

I tested new and old algorithms on examples below:

Example 1

code = """# start comment
if (False # inside comment
    and True): # condition comment
    # if comment
    a = 5
# before else comment
else: # false comment
    # else comment
    a = 6 # inline comment
# end comment"""

Output 1

Module(
    body=[
        Comment(
            value='# start comment',
            inline=False,
            lineno=1,
            col_offset=0,
            end_lineno=1,
            end_col_offset=15),
        If(
            test=BoolOp(
                op=And(),
                values=[
                    Constant(
                        value=False,
                        comment=Comment(
                            value='# inside comment',
                            inline=True,
                            lineno=2,
                            col_offset=10,
                            end_lineno=2,
                            end_col_offset=26),
                        lineno=2,
                        col_offset=4,
                        end_lineno=2,
                        end_col_offset=9),
                    Constant(
                        value=True,
                        comment=Comment(
                            value='# condition comment',
                            inline=True,
                            lineno=3,
                            col_offset=15,
                            end_lineno=3,
                            end_col_offset=34),
                        lineno=3,
                        col_offset=8,
                        end_lineno=3,
                        end_col_offset=12)],
                lineno=2,
                col_offset=4,
                end_lineno=3,
                end_col_offset=12),
            body=[
                Comment(
                    value='# if comment',
                    inline=False,
                    lineno=4,
                    col_offset=4,
                    end_lineno=4,
                    end_col_offset=16),
                Assign(
                    targets=[
                        Name(
                            id='a',
                            ctx=Store(),
                            lineno=5,
                            col_offset=4,
                            end_lineno=5,
                            end_col_offset=5)],
                    value=Constant(
                        value=5,
                        lineno=5,
                        col_offset=8,
                        end_lineno=5,
                        end_col_offset=9),
                    lineno=5,
                    col_offset=4,
                    end_lineno=5,
                    end_col_offset=9),
                Comment(
                    value='# before else comment',
                    inline=False,
                    lineno=6,
                    col_offset=0,
                    end_lineno=6,
                    end_col_offset=21)],
            orelse=[
                Comment(
                    value='# false comment',
                    inline=False,
                    lineno=7,
                    col_offset=6,
                    end_lineno=7,
                    end_col_offset=21),
                Comment(
                    value='# else comment',
                    inline=False,
                    lineno=8,
                    col_offset=4,
                    end_lineno=8,
                    end_col_offset=18),
                Assign(
                    targets=[
                        Name(
                            id='a',
                            ctx=Store(),
                            lineno=9,
                            col_offset=4,
                            end_lineno=9,
                            end_col_offset=5)],
                    value=Constant(
                        value=6,
                        lineno=9,
                        col_offset=8,
                        end_lineno=9,
                        end_col_offset=9),
                    comment=Comment(
                        value='# inline comment',
                        inline=True,
                        lineno=9,
                        col_offset=10,
                        end_lineno=9,
                        end_col_offset=26),
                    lineno=9,
                    col_offset=4,
                    end_lineno=9,
                    end_col_offset=9)],
            lineno=2,
            col_offset=0,
            end_lineno=9,
            end_col_offset=9),
        Comment(
            value='# end comment',
            inline=False,
            lineno=10,
            col_offset=0,
            end_lineno=10,
            end_col_offset=13)],
    type_ignores=[])

Example 2

code = """source = {
    # c1
    a: 1,
    b: 2,  # c2
}"""

Output 2

Module(
    body=[
        Assign(
            targets=[
                Name(
                    id='source',
                    ctx=Store(),
                    lineno=1,
                    col_offset=0,
                    end_lineno=1,
                    end_col_offset=6)],
            value=Dict(
                keys=[
                    Comment(
                        value='# c1',
                        inline=False,
                        lineno=2,
                        col_offset=4,
                        end_lineno=2,
                        end_col_offset=8),
                    Name(
                        id='a',
                        ctx=Load(),
                        lineno=3,
                        col_offset=4,
                        end_lineno=3,
                        end_col_offset=5),
                    Name(
                        comment=Comment(
                            value='# c2',
                            inline=True,
                            lineno=4,
                            col_offset=11,
                            end_lineno=4,
                            end_col_offset=15),
                        id='b',
                        ctx=Load(),
                        lineno=4,
                        col_offset=4,
                        end_lineno=4,
                        end_col_offset=5)],
                values=[
                    Constant(
                        value=1,
                        lineno=3,
                        col_offset=7,
                        end_lineno=3,
                        end_col_offset=8),
                    Constant(
                        value=2,
                        lineno=4,
                        col_offset=7,
                        end_lineno=4,
                        end_col_offset=8)],
                lineno=1,
                col_offset=9,
                end_lineno=5,
                end_col_offset=1),
            lineno=1,
            col_offset=0,
            end_lineno=5,
            end_col_offset=1)],
    type_ignores=[])

[margual56]

@t3rn0 Hello, I think kapulkin has made the requested changes. Maybe you could re-review this PR? Thank you!

[kapulkin]

Yes, I made an update with parsing bug fix.
So now the code is quite stable. I use it on a daily basis.

@margual56, thank you for pointing about the update.

[tristanlatr]

I believe it's still missing actual executable test cases in test_parse.py and test_unparse.py.

Also, since this proposal breaks the API of the library I think it should at least comes with the appropriate changes to the README.md file explaining the changes.

[t3rn0]

Sorry for such a late response.
This change seems broken to me. Example: there's no _Unparser definition which is used in unparse function (L241), and unparsing comments and putting them to their initial place is essential for #13.
+ there are no new test cases that would "freeze" the new features/fixes. Without it I see no reason to change anything.
I've made several attempts to work with this PR and the issue, but so far without success.

[kapulkin]

@t3rn0 thank you for the review. You are right about _Unparser, this is part of outdated code, I will remove it.

Indeed the code had also a few issues. During intensive code usage I found them and fixed few month ago on my machine. I updated the pull request now. Sorry for late update.

I agree, that future work on tests is needed to complete pull-request. Any hep here is appreciated. I will try to add tests from my side too.